施氮水平对不同切花菊品种生长及氮素累积和分配的影响OA北大核心CSTPCD

[Objectives]Aiming at the problems of excessive nitrogen fertilizer application,low nitrogen efficiency and unclear nitrogen uptake and allocation rules of chrysanthemum varieties with different nitrogen nutrient characteristics in chrysanthemum production,the effects of different nitrogen levels on the growth,nitrogen efficiency,nitrogen accumulation and allocation of different cut chrysanthemum varieties were investigated in this paper to clarify the characteristics of nitrogen uptake and utilization of different cut chrysanthemum varieties.The results of this study would provide a theoretical basis for efficient production of cut chrysanthemum.[Methods]The growth indexes,nitrogen efficiency indexes and nitrogen accumulation in different parts of 9 cut chrysanthemum varieties from different families were measured under high nitrogen(800 mg per plant),normal nitrogen(400 mg per plant)and low nitrogen(50 mg per plant)levels during the whole growth stage.[Results]The growth indexes such as plant height,stem diameter,leaf dry weight,stem dry weight,root dry weight,total root length,principal branch number,flower number,and nitrogen accumulation indexes such as root nitrogen accumulation,leaf nitrogen accumulation,plant nitrogen accumulation,increased with nitrogen level increasing,while the nitrogen efficiency indexes decreased with nitrogen level increasing.Under normal nitrogen level,the flower dry weight,crown breadth,flower diameter and flower nitrogen accumulation of 9 chrysanthemum varieties were the highest,and the flowering stage was the earliest.Under different nitrogen levels,'Nannonglihuang'was significantly higher than other varieties in stem diameter,biomass of each part,average root diameter,root volume,crown breadth,flower diameter,nitrogen uptake efficiency,agronomic nitrogen efficiency,plant nitrogen accumulation and flower nitrogen accumulation(P＜0.05).The plant height,stem diameter,biomass of each part,crown breadth,flower diameter,nitrogen uptake efficiency,agronomic nitrogen efficiency and plant nitrogen accumulation of'Nannongxuefeng'and'Nannongzifeng'were lower than those of other varieties.During the seedling stage and reproductive growth stage,leaf nitrogen accumulation of the 9 chrysanthemum varieties was the highest,followed by stem and root.At full-bloom stage,the proportion of nitrogen accumulation in leaves and stems decreased significantly,and the nitrogen accumulation in flowers was significantly higher than those in other organs.Under different nitrogen levels,plant nitrogen accumulation was significantly positively correlated with flower dry weight,crown breadth,flower diameter,principal branch number,flowering number and flowering date(0.39 ≤r≤0.83).And flower nitrogen accumulation was significantly positively correlated with flower dry weight and flowering date(0.53≤r≤0.89).[Conclusions]High nitrogen level promoted the vegetative growth of chrysanthemum,but inhibited the nitrogen efficiency and quality formation of chrysanthemum.The growth rule of chrysanthemum during the whole growth stage was consistent with nitrogen accumulation and allocation.Plant nitrogen accumulation and flower nitrogen accumulation played a key role in the formation of flowering quality of chrysanthemum.